msm: mdss: Change notify_update ioctl copy size to match ioctl definition

The MSMFB_NOTIFY_UPDATE ioctl is defined based on sizeof(unsigned int).
However, we use the incorrect size when copying to and from userspace.
The sizes for copying have been fixed to match the ioctl definition.

Change-Id: I0f63228e5b4ad936d89c5f2bcbd84204037a0edf
Signed-off-by: Benet Clark <benetc@codeaurora.org>